socket编程

Posted 2020-08-15

sicket编写了聊天小程序和猜数字大小小游戏，发现了一些问题，send函数参数中的字符串大小要用strlen（）来计算 而recv（）要用sizeof（）来计算或者指定大小，否则在多次接收发送中会出现问题只有第一次是正常的发送接收。

#pragma comment(lib,"ws2_32.lib")
#include<stdio.h>
#include<stdlib.h>
#include<winsock2.h>
#include<time.h>

void main()
{
    WSADATA        wsaData;
    SOCKET        ListeningSocket;
    SOCKET        NewConnection;
    SOCKADDR_IN ServerAddr;    
    SOCKADDR_IN ClientAddr;
    char        DataBuffer[1024];
    char        SendBuffer[1024];
    int            ClientAddrLen;
    int            Port = 5151;
    int            Ret;

    if((WSAStartup(MAKEWORD(2,2),&wsaData)) != 0)                    //通过WSAStarup()函数启动winsoock 2 API 参数为版本号和启用的WSADATA对象
    {
        printf("WSAStartup failed with erroe %d\n",Ret);
        return;
    }
    if((ListeningSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)) == INVALID_SOCKET)  //创建套接字socket() 参数为地址簇为AF_INET 流SOCK_STREAM,和 IP--- 代表TCP连接
    {
        printf("socket failed with error &d\n",WSAGetLastError());
        WSACleanup();
        return;
    }
    ServerAddr.sin_family = AF_INET;                        //协议
    ServerAddr.sin_port = htons(Port);                        //要监听的端口号
    ServerAddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);    //服务器端监听所有的IP地址

    if(bind(ListeningSocket,(SOCKADDR*)&ServerAddr,sizeof(ServerAddr)) == SOCKET_ERROR)  //把套接字和服务端地址绑定
    {
        printf("bind failed with error %d\n",WSAGetLastError());
        closesocket(ListeningSocket);
        WSACleanup();
        return;
    }

    if(listen(ListeningSocket,5) == SOCKET_ERROR)         //利用服务端套接字进行监听 5是最大排队等待连接数
    {
        printf("listen failed with error %d\n",WSAGetLastError());
        closesocket(ListeningSocket);
        WSACleanup();
        return;
    }

    ClientAddrLen = sizeof(SOCKADDR);
    printf("等待客户端连接.......\n");
    if((NewConnection = accept(ListeningSocket,(SOCKADDR*)&ClientAddr,&ClientAddrLen)) == INVALID_SOCKET)    //接收客户端的连接请求
    {
        printf("accept failed with error %d\n",WSAGetLastError);
        closesocket(ListeningSocket);
        WSACleanup();
        return;
    }
    int i,j,n=0;
    char num[1024];
    srand((unsigned)time(NULL));
    i = rand()%300;
    printf("产生的随机数为:%d\n",i);
    itoa(i,num,10);
    if((Ret = send(NewConnection,num,strlen(num),0)) == SOCKET_ERROR)
    {
        printf("send failed with error%d\n",WSAGetLastError());
        closesocket(NewConnection);
        WSACleanup();
        return;
    }
    while(1)
    {
        if((Ret = recv(NewConnection,DataBuffer,sizeof(DataBuffer),0))== SOCKET_ERROR)
        {
            printf("recv failed with error %d\n",WSAGetLastError());
            closesocket(NewConnection);
            WSACleanup();
            return;
        }
        //printf("接收到的字符串%s\n",DataBuffer);
        n++;
        printf("第%d次猜测\n",n);
        DataBuffer[Ret] = ‘\0‘;
        j = atoi(DataBuffer);
        printf("接受到的值%d\n",j);
        if(j > i)
        {
            SendBuffer[0] = ‘1‘;
            SendBuffer[1] = ‘\0‘;
            if((Ret = send(NewConnection,SendBuffer,strlen(SendBuffer),0)) == SOCKET_ERROR)
            {
                printf("send failed with error%d\n",WSAGetLastError());
                closesocket(NewConnection);
                WSACleanup();
                return;
            }
        }
        else if(j < i)
        {
            SendBuffer[0] = ‘2‘;
            SendBuffer[1] = ‘\0‘;
            if((Ret = send(NewConnection,SendBuffer,strlen(SendBuffer),0)) == SOCKET_ERROR)
            {
                printf("send failed with error%d\n",WSAGetLastError());
                closesocket(NewConnection);
                WSACleanup();
                return;
            }
        }
        else if(j == i)
        {
            SendBuffer[0] = ‘3‘;
            SendBuffer[1] = ‘\0‘;
            if((Ret = send(NewConnection,SendBuffer,strlen(SendBuffer),0)) == SOCKET_ERROR)
            {
                printf("send failed with error%d\n",WSAGetLastError());
                closesocket(NewConnection);
                WSACleanup();
                return;
            }
            break;
        }
    }
    closesocket(ListeningSocket);
    closesocket(NewConnection);
    WSACleanup();
}

#pragma comment(lib,"ws2_32.lib")
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#include<winsock2.h>

//void main(int argc,char **argv)            //argc表示后面有几个参数，argv是值是字符数组，顺序与输出时不一一对应 这样需要用CMD到目录去打开！！！
void main()
{
    WSADATA        wsaData;
    SOCKET        s;
    SOCKADDR_IN    ServerAddr;
    int            Ret;
    int            Port=5151;
    char        sendBuffer[1024];
    char        tempBuffer[1024];

    //if(argc <= 1)
    //{
    //    printf("USAGE: TCPClient <Server IP address>.\n");
    //    return;
    //}

    if((Ret = WSAStartup(MAKEWORD(2,2),&wsaData)) != 0)
    {
        printf("WSAStartup failed with error %d\n",Ret);
        return;
    }

    if((s = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)) ==INVALID_SOCKET)
    {
        printf("socket failed with error %d\n",Ret);
        return;
    }

    ServerAddr.sin_family = AF_INET;
    ServerAddr.sin_port = htons(Port);
    //ServerAddr.sin_addr.S_un.S_addr = inet_addr(argv[1]);
    ServerAddr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    
    if(connect(s,(SOCKADDR*)&ServerAddr,sizeof(ServerAddr)) == SOCKET_ERROR)
    {
        printf("connect failed with error %d\n",WSAGetLastError());
        closesocket(s);
        WSACleanup();
        return;
    }
    printf("连接服务器成功！\n");
    printf("猜数字小游戏：服务器已经生成了一个数字，猜一猜是多少？\n");
    char num[1024];
    int a;
    if((Ret = recv(s,num,sizeof(num),0)) == SOCKET_ERROR)
    {
        printf("recv failed with error %d\ne",WSAGetLastError());
        closesocket(s);
        WSACleanup();
        return;
    }
    a = atoi(num);
    while(1)
    {
        int i;
        printf("请输入你猜测的数：\n");
        gets(sendBuffer);
        if((Ret = send(s,sendBuffer,strlen(sendBuffer),0)) == SOCKET_ERROR)
        {
            printf("send failed with error%d\n",WSAGetLastError());
            closesocket(s);
            WSACleanup();
            return;
        }
        if((Ret = recv(s,tempBuffer,sizeof(tempBuffer),0)) == SOCKET_ERROR)
        {
            printf("recv failed with error %d\ne",WSAGetLastError());
            closesocket(s);
            WSACleanup();
            return;
        }
        tempBuffer[Ret] = ‘\0‘;
        //printf("接收的字符串%s\n",tempBuffer);
        //i = atoi(tempBuffer);
        //printf("接受到的值%s\n",i);
        if(tempBuffer[0] == ‘1‘)
        {
            printf("你猜的数太大了，换一个小的试试！\n");
        }
        else if(tempBuffer[0] == ‘2‘)
        {
            printf("你猜的数太小了,换一个大的试试！\n");
        }
        else if(tempBuffer[0] == ‘3‘)
        {
            printf("恭喜你猜对了，最终答案是：%d\n",a);break;
        }
        ZeroMemory(tempBuffer,1024);
        ZeroMemory(sendBuffer,1024);
    }
    closesocket(s);
    WSACleanup();
}